1. Field of the Invention
This invention relates to a means to mount and adjust reflecting surfaces such as mirrors and the like.
More particularly, this invention describes and claims a means to position laser mirrors in tip and tilt about an orthogonal axis plus planar translations perpendicular to the mirror surface.
2. Description of the Prior Art
Conventional mirror mounts such as those associated with optical labs and telescopes are generally not suitable to position mirrors utilized in the large laser field of technology.
Typically, conventional mirror mounts are suspended from a base support structure by a system of screw jacks and springs.
These devices are unsuitable in a severe vibration environment commonly associated with, for example, a large laser lab where a system of high-power laser resonator mirror mounts must support mirrors weighing from 25 to 40 pounds each.
Laser mirrors are normally affixed to a plate that is suspended from and movable with respect to a backup support plate firmly mounted to an optical "bench". Since laser beams are generally directed substantially horizontally, the mirror surfaces are generally perpendicular to gravitational forces. Thus, the mirrors are cantilevered from the surface of the support backup plate and must rigidly support a relatively heavy weight suspended therefrom.
A series of springs in conventional mounts between the rigid support plate and the movable plate from which the mirror is mounted provides a force that maintains one or more mirror actuators in compression or tension, thereby stabilizing the mirror. However conventional type spiral springs have little or no resistance to shear forces which are large in heavy laser mirrors cantilevered from a rigid mount. Therefore pins or ball type sockets are generally required to support the movable plate in shear. These supporting devices introduce frictional hysteresis that inherently reduces the required positional accuracy of laser mirrors.
Additionally, where screw type actuation is manually or mechanically manipulated to position mirrors, some type of locking mechanism is required. During activation of the locking mechanism positioning errors may be introduced. For example, the simple procedure of tightening a set screw to "lock" a mirror usually requires much tedious and time consuming trial and error to align one or more mirrors to a desired setting.
The present invention effectively eliminates frictional hysteresis associated with conventional ball or pin supports as well as eliminating the need for mechanical types of locking mechanisms.
In a large laser system several mirrors are located inside vacuum enclosures. Precise positioning requires that these mirrors be adjusted with the vacuum system activated. A remote positioning capability is required which is not found in conventional mounts.